On Thursday, Michelin, which was the first significant backer of engineer Ben Bowlby's radical new race car design, said that it would not supply tires for the DeltaWing's return to competition in March at the Mobil1 12 Hours of Sebring. Bridgestone/Firestone has been rumored as a replacement, but Speyer said the program is one of many it is considering. "It's nice to be in a position that people want us to partner with them on various projects," Speyer said. He added that the company's top racing priority in the U.S. is the IndyCar series, "and we can't take on anything on that would jeopardize that. It's not going to happen."

Speyer did say that the short time frame -- the 12 Hours is March 16 -- is a consideration. Michelin spent heavily on research to make sure the ultralight tires -- especially the front tires, which are just four inches wide -- were appropriate for the car's dual mission of excellent handling and maximum tire wear.

The DeltaWing debuted three years ago at the 2010 Chicago Auto Show as a candidate to replace the then-current IndyCar design. The show cars were shod with Firestone Firehawk tires because of the IndyCar connection, but those tires were never developed for on-track use. In 2011 Michelin stepped in at the 24 Hours of Le Mans to back the car's run at the 2012 24 Hours, giving the project credibility it needed to attract other backers.

Speyer would not comment on whether the fact that most of the original participants in the DeltaWing project, including designer Ben Bowlby and builder All-American Racers, headed by Dan Gurney, have left the project would have an impact on Bridgestone/Firestone's ultimate decision.